The present invention relates generally to a solar power plant, and more particularly to heliostat tracking calibration in a central tower receiver solar power plant.
In a central tower receiver power plant, an array of heliostats reflects sunlight toward a receiver mounted atop a tower. One type of receiver converts incident radiant energy into output high-pressure, high-temperature steam, which can later be fed to a turbine for electrical power generation. Heliostats are generally mounted on the ground in an area about the tower. Each heliostat has a rigid reflective surface capable of suntracking, that is, the surface takes on orientations throughout the day so as to maintain reflection of the moving sun onto the receiver. Highly accurate suntracking is desirable as it minimizes spillage of reflected light around the receiver and allows some control of the flux pattern incident on the receiver surfaces.
In a large power plant, there may be hundreds to hundreds of thousands of heliostats. Besides suntracking accuracy, it is additionally desirable that the heliostats be economically manufactured and installed. In turn, this may be associated with mechanical tolerances and other limitations that adversely affect suntracking accuracy. Accordingly, it is desirable to create a system that properly estimates the tolerances, to execute suntracking in a calibrated manner, achieving little or no spillage losses.